Core drilling



W. .j a

United Seite e f V 2,893,691 Y Y coR'nRnLlNG Theodore charles whifcpmb' Joh'ii'sn, iphanpesbiirg,

Union ofSouth Africa application March is, 195s', serial Np. 511,232 i claims priority, applicati@ Unitinfpr smh Africa March 1751955V -v s claims. (ci. :ss- 1.4)

Soft or friable cores such assand, `coal or thelikeSVa-re diicult to hold and extract with .knownhollow core .barrels' due to the cores disintegrating and crumbling. vCore catchers using a wedging 'actionon-.the core'. andpositioned' at the bottom of an iassociatedacore barrelare well known. Collapsing fingers to cut olf-and hold soft cores h ave also been used. All these core catchers may 'be operated by hydraulic pressure controlled by, a drop ball valve in the drilling tube. I It is an object of this invention to provide an improved .means for retaining cores and particularly softcores in a core barrel during retraction of an associated drilling tube fromthedrilledhole. v i

In accordance withthisinventiomin .a core drill having an inner and outer'tube rwith'provison for a drop valve for the inner tube, .there is provided a-'portion of fawall inthe length of the corebarrelrconstructed ofA pliable material with means for applying hydraulicpressure between the outer tube and Saidpliable portion` to .c ollapse the latter inwardly. Y,

The invention also provides for the pliable portion lto be formed of two concentric tubes and for the annulus between them to be closed at the top and bottom by the circular wall of the divided core barrel, and also for the annulus to have a lling of dough like material and escape holes in the inner tube for the escape of a portion of the filling on the collapse of the pliable portion.

The invention also provides means for blocking the flow of water about the pliable portion of the core barrel for making the pliable portion co-operate in the control of a core spring.

The invention is illustrated in the accompanying drawings in which:

Fig. l is a view of a rotary core drill, partly in section.

Fig. 2 is a view of part of the core drill shown in Fig. l with a portion of the captured core.

Fig. 3 is a view 'similar to Fig. 1 but showing a modification and,

Fig. 4 shows a core spring in its open position.

Referring to Fig. 1 of the drawings, the rotary drill stem 1 is detachable from an outer tube 2 which houses an inner tube 3 having its upper end forming a piston like part 4 capable of downward movement, as hereinafter described, for trapping a core. The piston 4 terminates in a core barrel 5. The lower end of core barrel 5 is provided with a length of tubing 6 (Fig. 2) with, in the example shown, a concentric inner tube 7 to provide an annulus 8 between them. These tubes 6, 7, are made of a pliable but inelastic material (such as a waterproof fabric, sheet lead, soft steel, copper or other suitable matrial) and there is a second annulus 9 provided between the reaming shell or tube 2 and the outside wall of the outer pliable tube 6.

When the core is to be lifted, a drop ball valve 10 is 2. used which, in well known manner, partially blocks the central passage of water through the piston 4.

The drop valve 10 allows some water to pass but restricts it suciently for the pressure to increase above piston 4 to move it downwardly and water passing valve 10 escapes through ports 23 into annular groove 11 and so into annulus 9. The downward movement of the pistonv 4 and therefore core barrel 5 brings the bottom edges of tube 6 in contact with a swage ring 12 to bend the tube 6 outwardly and close the bottom of annulus 9. Pressure in the core drill is at once exerted in the annulus 9 and under the pressure the tubes 6, 7 are bellied inwardly to form a closure of the core barrel 5 as shown in Fig. 2. There will then be no hydraulic water flowing through the core barrel 5 and its extension 6, 7 and what water there is runs out in normal manner until the ports at the swage block 12 are closed by the downward movement of tube 6. Any water coming down the drill rod which does not enter annulus 9 will escape through ports 24.

If it is desired only one tube 6 -may be used but if the two are used as shown the annulus 8 between the tubes 6, 7 may be filled with a dough-like material`13, preferably a substance unaffected by water such as putty, plasticine or the like.

When the use of the material 13 and collapse ofthe tubes 6, 7, the material 13 will be squeezed out through holes 14 in the inner tube 7 and form plugs 1S as shown in Fig. 2 to hold any soft material which may have entered the core barrel 5.

It is often desirable not only to lift friable or semi-wet material in core barrel 5 but also more solid cores.

To enable this to be done, a core spring 16 is provided as shown -in Figs. 3 and 4.

In'Fig. 3, the bottom end of the tool is elongated so that a core spring 16 can be accommodated below the swage ring 12. The tube 7 is extended and also the part 17 which lills the lower part of the annulus between tubes 6 and 7. The bore of the core spring 16 is large enough to embrace the extended portion of tube 7 but not the part 17.

The core spring 16 is kept expanded by a sheet metal piece 18 (Fig. 4) which is adapted to buckle when its extensions 21 are pressed inwardly by bevelled portion 22 of the lower portion of the drilling member.

As the tubes 6, 7 with the part 17 move downwardly, due to the blockage of the annulus 9 by the end of the tube 6 which is swaged outwardly by contact with the swage block 12, the core spring 16 is forced down to the position shown by the dotted lines in Fig. 3 where it grips the lower portion of the core in core barrel '5.

It will be understood that the action of the core barrel 5 illustrated in Fig. 3 is such that not only is friable material captured but, if there is a solid core, it will be held by the core `spring 16. y

In using this invention the drill bit 19 is operated in the normal manner. When it is necessary to raise the core, the ball valve 10 is dropped onto its seal and the hydraulic pressure of the water supply to the bit acts on the piston 4 to force it from its retaining circlip 20. As described above, the piston 4 terminates in the core barrel 5 and the downward movement of the core barrel 5 operates the core spring 16 if present at the lower end 5a of the core barrel 5. Whether the core spring 16 is used or not the pliable shell section shown by the tubes 6 and 7 ofthe core barrel 5 is subjected to pressure as above described. The pressure applied in the annulus 9 together rwith the downward movement of the core barrel 5 causes deformation of the pliable shell section which tends to collapse inwardly anywhere throughout its length towards the center of the core barrel 5. A total collapse takes n.9 place if the core is soft and so closes the barrel as to prevent any loss or" the core from above this point during the raising operations of the core drill.

With the collapse of this pliable section of the core barrel 5, some of the dough-like material 13 isejected through the holes 14 in the inner tube '7 and forms a plug 15 to block any opening left at the center of the collapsed pliable portion of the core barrel 5.

The hydraulic pressure is automatically reduced during the raising operation (since with the removal of drilling rods an equivalent head of water is removed) but'the pliable section of the core barrel 5 formed by a tube 6 or as shown by the tubes 6 and 7 due to the inherent inelasticity of the material of which the pliable portion` is constructed, remains in the collapsed position described. Should the core be solid rock the pliable portion cannot fully collapse but will aid the normal core spring 16 to retain the core.

The pliable portion of the core barrel can be replaceable, or a core barrel plug, not shown, may be used to restore the barrel to its original shape after deformation.

The invention provides a means for avoiding core loss during the raising of a rotary core drill and is particularly suitable for use when soft cores are encountered.

What I claim is:

1. Apparatus for obtaining and removing cores of material to be inspected comprising an outer tubular member insertable into the material and defining an axial bore, an inner member slidable in said axial bore and deiining a central bore for the admission of a pressure medium, a valve in said central bore for controlling the flow of the pressure medium, said inner member defining an annular chamber with said outer member toward an end of the latter and at least one passage between the central bore and said chamber, said inner member including7 a main portion and an axially spaced portion at said end, and substantially flexible and collapsible means between said main portion and spaced portion and defining an annular chamber with the outer member, the annular chambers having connection, pressure on the main portion causing the same to slideftoward said spaced portion and tending to collapse said means, and pressure in the annular chambers collapsing said means to trap matrial which has entered said end of the outer member.

2. Apparatus as claimed in claim 1 comprising a swage ring supported on said outer tubular member, said means comprising at least oneexible cylinder having an end receivable by said ring whereby said end is dared to control the collapsing of the cylinder.

3'; Apparatus as claimed in clai'rn l wherein said means comprises concentric `exible and non-elastic cylinders and a Adough-like material therebetween, the inner of said cylinders defining radial openings whereby the dough-like material can enterintoft'he inner cylinder to form a seal.

4. Apparatus as claimed in claim l, wherein said spaced portion has a wedge-like coniiguraton, said apparatus further comprising an annular spring between said main and spaced portions and forcible by the main portion against Said spaced portion` for securing the material.

5. Apparatus forobtaini'ng cores comprising an outer member and inner member accommodated within the outer memberandldeiining` at an end of the' outer member, an annular chamber; said inner member comprising: a slidable piston portionvdening 'a bore communicating with said=annular chamber, an end portion at the end of the outer membenrand at least one collapsible tubebetween said piston and end portions, said portions and tube 'delining a spaceto accommodate a core of material to be sampled, a movement of the piston portion toward' the end portion and pressure applied in the annular chamber via saidborecollapsng said tubeto trap a core.

References Cited in the le of this patent UNITED STATES PATENTS 1,952,170 Humason et a1 Mar. 27,1934 Vv2,038,793 Howard et al Y Apr. 28, 1936 2,126,684V numasoneral. Auge, 1938 2,643,858l Hardman rl June 30, 195s 2,690,806 Britton er ai. A l oet, 5, 1.954 

